A few years ago, I asked a pregnant friend what she'd do if her baby was born fugly. "I'd want people to lie," she said. "I'd want people to tell me she's the most beautiful baby in the world." Isn't that rather meaningless?

Baroness Susan Greenfield, a controversial neuroscientist, has an idea. It’s been hard to pin down exactly what that idea is, because rather than publishing a proper explanation of it, she’s spent the last few years promoting scare-stories about the...